Liquid crystal display device and method for manufacturing the same

ABSTRACT

An LCD device having improved connection stability concerning a COG, a COF or an FPC and a method for manufacturing the LCD device are disclosed. A pixel including a TFT as a switching device is formed at a central portion corresponding to an active region of a substrate. A gate and a data input pads are formed at a peripheral portion corresponding to a pad region of a substrate. An organic insulation layer is formed on the whole surface of the substrate having the TFT the pads thereon. A rugged structure is formed on the organic insulation layer for forming a rugged reflection electrode by exposing and developing the organic insulation layer. An organic insulation layer is formed to reduce a step between the pads and the portion adjacent to the pads. A single organic insulation layer or double organic insulation layers can be formed. A connection failure between the pads and the COG, the COF or the FPC can be greatly reduced since the height difference of the organic insulation layer between the pads the portion adjacent to the pads can be minimized through the exposing and the developing processes. Also, an electrical short between the pads can be prevented because the organic insulation layer is interposed between the pads.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method for a liquid crystaldisplay device (LCD) and a method for manufacturing the same, moreparticularly to an LCD device having enhanced connection stabilitybetween a driving circuit of the LCD device and chip on glass (COG), achip on film (COF) or a flexible printed circuit film (FPC) and a methodfor manufacturing the same.

[0003] 2. Description of the Related Art

[0004] In the information society of the present time, electronicdisplay devices are more important as information transmission media andvarious electronic display devices are widely applied for industrialapparatus or home appliances. Such electronic display devices are beingcontinuously improved to have new appropriate functions for variousdemands of the information society.

[0005] In general, electronic display devices display and transmitvarious pieces of information to users who utilize such information.That is, the electronic display devices convert electric informationsignals outputted from an electronic apparatus into light informationsignals recognized by users through their eyes.

[0006] The electronic display devices are generally divided intoemissive display devices and non-emissive display devices. The emissivedisplay devices display light information signals through emittinglights and the non-emissive display device displays the lightinformation signals through reflection, a scattering or an interference.The emissive display devices include a cathode ray tube (CRT), a plasmadisplay panel (PDP), a light emitting diode (LED) and anelectroluminescent display (ELD). The emissive display devices arecalled as active display devices. Also, the non-emissive displaydevices, called as passive display devices, includes a liquid crystaldisplay (LCD), an electrochemical display (ECD) and an electrophoreticimage display (EPID).

[0007] The CRT has been used for television sets or computer monitors asthe display device for a long time since it has a high quality and a lowmanufacturing cost. The CRT, however, has some disadvantages such as aheavy weight, a large volume and high power dissipation. For thesereasons, recently the demand for new electronic display devices has beengreatly increased, such as a flat panel display device which hasexcellent characteristics, for example, a thin thickness, a lightweight, a low driving voltage and a low power consumption. Such flatpanel display devices can be manufactured using the rapidly improvingsemiconductor technology.

[0008] In the flat panel devices, liquid crystal display (LCD) deviceshave been widely utilized for various electronic devices because the LCDdevices are thin, and has low power dissipation and high displayqualities approximately identical to those of the CRT. Also, the LCDdevice can operate under a low driving voltage and can be easilymanufactured.

[0009] The LCD devices are generally divided into a transmissive typeand a reflection type. The transmissive type LCD device displaysinformation by using an external light source and the reflection typeLCD device displays information by using ambient light. Themanufacturing processes for the trasmissive or the reflection type LCDdevice are already disclosed in various literatures.

[0010]FIGS. 1A, 1B and 1C depict the cross-sectional views of aconventional method for manufacturing a LCD device.

[0011] Referring to FIG. 1A, after a metal layer such as an aluminum(Al) layer or a chrome (Cr) layer is formed on a substrate 10 composedof an insulating material, the metal layer is patterned to form a gateelectrode 15 and a gate pad 20. Then, a gate insulation layer 25 isformed on the whole surface of the substrate 10 where the gateinsulation layer 25 formed by depositing silicon nitride and by a plasmachemical vapor deposition method.

[0012] Subsequently, amorphous silicon and an in-situ doped n+amorphoussilicon are formed on the gate insulation layer 25 and are patterned andan amorphous silicon layer 30 and an ohmic contact layer 35 are formedon the gate electrode 15.

[0013] Then, a metal such as molybdenum (Mo), aluminum, chrome ortungsten (W) is deposited on the gate electrode 15 and patterned to forma source electrode 40 and a drain electrode 45. Hence, a thin filmtransistor (TFT) 60 having the gate electrode 15, the amorphous siliconlayer 30, the ohmic contact layer 35, the source electrode 40 and thedrain electrode 45 is formed in an active region 50 of the substrate 10besides a pad region 70 of the substrate 10 corresponding to aperipheral portion of the active region 50.

[0014] Referring to FIG. 1B, an organic insulation layer 75 composed ofan organic resist is formed on the active and the pad regions 50 and 70of the substrate 10 so that a lower substrate of the LCD device iscompleted.

[0015] With reference to FIG. 1C, a mask (not shown) is positioned overthe organic insulation layer 75 in order to from a contact hole 80 and apad opening 81. Then, the contact hole 80 exposing the drain electrode45 is formed in the organic insulating layer 75 after the organicinsulation layer 75 is exposed and developed by using the mask. In thiscase, the pad opening 81 partially exposing the gate pad 20 is formed inthe pad region 70 by simultaneously removing the gate insulation layer25 under the organic insulation layer 75.

[0016] Subsequently, after a metal having an excellent reflectivity suchas aluminum or nickel (Ni) is coated in the contact hole 80 and on theorganic insulation layer 75, the metal is patterned to form a reflectionelectrode 85 having a predetermined shape of a pixel. At that time, apad electrode 86 is formed in the pad opening 81 and on the organicinsulation layer 75 positioned a peripheral portion of the pad opening81 in the pad region 70.

[0017] Then, an orientation layer is formed on the resultant structureand an upper substrate (not shown) corresponding the lower substrate isprepared. The upper substrate includes a color filter, a transparentelectrode and an orientation layer. Continuously, several spacers areinterposed between the upper substrate and the lower substrate tocombine the upper substrate with the lower substrate and a liquidcrystal layer is formed between the upper substrate with the lowersubstrate, thereby accomplishing the LCD device.

[0018] In order to apply a driving signal to the LCD device fromoutside, a chip on glass (COG), chip on film (COF) or flexible printedcircuit film (FPC) is connected to the LCD device as a connectiondevice.

[0019] In the conventional method for manufacturing the LCD device,however, since the organic insulation layer or a layer having thickthickness is formed on the TFT as a protection layer, the connectionfailure between an external device and the LCD device may occur due tothe step between the pad region having the metal formed thereunder andthe peripheral region when the external device such as the COG, the COFor the FPC is connected to the pad region of the LCD device.

[0020]FIG. 2 is a cross-sectional view for showing the external deviceconnected to the pad region of the LCD device in FIG. 1C. Referring toFIG. 2, the opening 81 is formed by exposing and developing the organicinsulation layer 75 after the organic insulation layer 75 is coated onthe pad region 70 including the pad 20, and then the pad electrode 86 isformed in the opening 81 and on a portion of the organic insulationlayer 75 positioned near the opening 81.

[0021] Subsequently, in order to combine the pad electrode 86 with theCOG or the COF, output ends of the COG or the COF or bumps 94 of inputportion of the COG or the COF are aligned with the pad electrode 86after an anisotropic conductive film 90 having conductive balls 92 ispositioned on the pad electrode 86. Continuously, the pad electrode 86and the bumps 94 are electrically connected to each other through theconductive balls 92 by a compression process.

[0022] The organic insulation layer 75 coated on the pad region 70 isformed thick enough to protect the TFT and to form the reflectionelectrode 85. This creates a high step of about 3 to 4 μm between oneportion of the pad region 70 where the pad 20 is positioned and theother portion of the pad region 70. When the COG or the COF is connectedto such pad region 70 by the compression process, the connection betweenthe pad 20 and the COG or the COF may fail in the pad opening 81 due tothe step in the pad region 70 as shown in FIG. 2. Thus, the LCD devicemodule may not operate or operate improperly due to the connectionfailure.

[0023] In particular, the connection failure between the COG and the padmay be increased since the COG is connected to the pad by using theconductive ball with a diameter of about 5 μm during the conventionalcompression process.

[0024] Also, electrical shorts between adjacent pads become more likelymay be increased when the organic insulation layer formed on the padsand the peripheral region is removed because the organic insulationlayer prevents the electrical short between the adjacent pads among aplurality of pads, whereby reducing the reliability of the product.Therefore, the organic insulation layer positioned around the pad shouldbe not removed.

SUMMARY OF THE INVENTION

[0025] It is therefore a first objective of the present invention toprovide a liquid crystal display (LCD) device having improved connectionstability by minimizing a step between a pad region and an adjacentregion thereof when a chip on glass (COG), a chip on film (COF) or aflexible printed circuit (FPC) is connected to a driving circuit of theLCD device.

[0026] It is a second objective of the present invention to provide amethod for manufacturing the LCD device having enhanced connectionstability by minimizing the step between the pad region and the adjacentregion thereof when the COG, the COF or the FPC is connected to thedriving circuit of the LCD device.

[0027] To accomplish the first objective of the present invention, onepreferred embodiment of the present invention provides a display devicecomprising a substrate having a first region and a second region and aninsulation layer formed on the first and the second regions. The firstregion includes a pixel region where a pixel is formed to produce animage and a peripheral (outer) region surrounding the pixel region. Thesecond region has a pad connected to the pixel for applying anelectrical signal to the pixel from outside. The insulation layer has anopening formed in the second region to expose the pad. A secondthickness of the insulation layer around the opening is less than afirst thickness of the insulation layer in the peripheral region.

[0028] Also, to accomplish the first objective of the present invention,another preferred embodiment of the present invention provides areflection type liquid crystal display device comprising a firstsubstrate having a first region and a second region, a second substrateopposed to the first substrate, a liquid crystal layer, a reflectionelectrode formed at the central portion of the first substrate, and anorganic insulation layer. The first region of the first substrateincludes a pixel region at a central portion of the first substratewhere a pixel is formed to produce an image and a peripheral regionsurrounding the pixel region and a pad connected to the pixel is formedin the second region for applying an electrical signal to the pixel fromoutside. The liquid crystal layer is formed between the first and thesecond substrates and the reflection electrode has a rugged structurecomposed relatively high and relatively low portions. The organicinsulation layer is formed between the first substrate and thereflection electrode and also is formed in the first and the secondregions. The organic insulation layer has a rugged structure identicalto the rugged structure of the reflection electrode at a central portionof the first region and an opening in the second region to expose thepad. A second thickness of the organic insulation layer around theopening is less than a first thickness of the organic insulation layerin the peripheral region.

[0029] To accomplish the second objective of the present invention, onepreferred embodiment of the present invention provides a method formanufacturing a display device comprising the steps of:

[0030] forming a pixel in a pixel region of a first region of asubstrate, the first region including the pixel region and a peripheralregion around the pixel region, and forming a pad in a second region ofthe substrate for applying an electric signal to the pixel;

[0031] forming an insulation layer having an opening in the secondregion to expose the pad and wherein the insulation layer being formedin the first region and the second region and a second thickness of theinsulation layer around the opening is less than a first thickness ofthe insulation layer in the first region; and forming a pad electrode inthe opening and on the insulation layer formed around the opening in thesecond region.

[0032] The pixel region is positioned at a central portion of thesubstrate and the second region is positioned in the peripheral regionof the substrate. The pixel comprises a thin film transistor as aswitching device and the pad comprises a gate input pad and a data inputpad for applying an electric signal to the switching device. Preferably,the method further comprises forming a reflection electrode on theinsulation layer in the pixel region and forming a pad electrode on thepad in the second region.

[0033] According to one embodiment of the present invention the step forforming the insulation layer is performed by forming a first insulationlayer on the substrate, selectively removing the first insulation layerin the second region, forming a second insulation layer in the firstregion and in the second region, and forming the opening in the secondinsulation layer.

[0034] The step for removing the first insulation layer in the secondregion is performed by forming a contact hole in the first insulationlayer for connecting the pixel, fully exposing the first insulationlayer with an exposure amount for forming the contact hole after a firstmask is positioned over the first insulation layer to remove the firstinsulation layer and developing the exposed first insulation layer.

[0035] The step for forming the opening in the second insulation layeris performed by forming a rugged structure on the second insulationlayer after a second mask is positioned over the second insulationlayer, exposing the second insulation layer with an exposure amountidentical to an exposure amount for forming the rugged structure afterthe second mask for forming the opening is positioned over the secondinsulation layer, and developing the exposed second insulation layer.

[0036] According to another embodiment of the present invention the stepfor forming the insulation layer is performed by forming a firstinsulation layer on the substrate, patterning the first insulation layerto form an insulation layer pattern in the pixel region and toselectively remove the first insulation layer in the second region,forming a second insulation layer in the first and the second regions,and forming an opening in the second insulation layer in the secondregion.

[0037] The step for patterning the first insulation layer is performedby positioning a first mask on the first insulation layer for forming arugged structure and a contact hole, fully exposing the first insulationlayer with an exposure amount for forming the contact hole, anddeveloping the exposed first insulation layer.

[0038] The step for forming the opening is performed by positioning asecond mask over the second insulation layer for forming the contacthole and the opening, exposing the second insulation layer anddeveloping the exposed second insulation layer.

[0039] According to still another embodiment of the present inventionthe step for forming the insulation layer is performed by forming anorganic insulation layer on the substrate, primarily exposing theorganic insulation layer with a full exposure amount for removing theorganic insulation layer on the pad, partially exposing the organicinsulation layer in the second region, and forming an opening in thesecond region and partially removing the organic insulation layer aroundthe opening in the second region by developing the exposed organicinsulation layer.

[0040] The step for primarily exposing the organic insulation layer isperformed by exposing the organic insulation layer with a full exposureamount after a first mask is positioned over the organic insulationlayer for forming the opening and a contact hole for electricallyconnecting the pixel.

[0041] The step for partially exposing the organic insulation layer isperformed by exposing the organic insulation layer and the second regionwith a lens exposure amount for forming a reflection electrode on theorganic insulation layer.

[0042] According to the present invention, it can be minimized that thedifference in height between one portion of the organic insulation layerin the pad region and the other portion of the organic insulation layeradjacent to the pad region by exposing and developing single organicinsulation layer or double organic insulation layers. Therefore, theconnection failure between the pads of the LCD device and the COG, theCOF, the FPC can be greatly decreased when the COG, the COF, the FPC iscompressed to the pads of the LCD device. Also, the electrical shortbetween the pads of the LCD device can be prevented since the organicinsulation layer remains between the pads while the step between thepads is greatly decreased. Furthermore, the step in the pad region canbe minimized without performing another process for reducing the stepsince it is reduced that the height difference between the heightdifference between one portion of the organic insulation layer in thepad region and the other portion of the organic insulation layeradjacent to the pad region when the organic insulation layer is exposedand developed so as to from the contact hole and the reflectionelectrode.

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The above objective and advantages of the present invention willbecome more apparent by describing in detail preferred embodimentsthereof with reference to the attached drawings, in which:

[0044]FIGS. 1A, 1B and 1C are cross-sectional views showingmanufacturing steps of the conventional liquid crystal display device;

[0045]FIG. 2 is a cross-sectional view showing an external deviceconnected to a pad region in FIG. 1C;

[0046]FIG. 3 is a plane view illustrating a method for manufacturing aliquid crystal display device according to a first embodiment of thepresent invention;

[0047]FIGS. 4A, 4B, 4C, 4D, 4E and 4F are cross-sectional views takenalong the line of A-A′ in FIG. 3 so as to illustrate manufacturing stepsof the liquid crystal display device according to the first embodimentof the present invention;

[0048]FIGS. 5A, 5B, 5C and 5D are cross-sectional views for illustratinga method for manufacturing a liquid crystal display device according toa second embodiment of the present invention; and

[0049]FIGS. 6A, 6B, 6C and 6D are cross-sectional views for illustratingsteps for forming an organic insulation layer according to a thirdembodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0050] Hereinafter, the present invention will now be described morefully with reference to the accompanying drawings, in which preferredembodiments of the present invention are shown. The present inventionmay, however, be embodied in many different forms and should not beconstrued as being limited to the embodiments set forth herein. Rather,these embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey the concepts of the presentinvention to those skilled in the art. Throughout the accompanyingdrawings, the thicknesses and the dimensions of the various layers andregions are exaggerated for clarity.

Embodiment 1

[0051]FIG. 3 is a plane view illustrating a method for manufacturing anLCD device according to a first embodiment of the present invention andFIGS. 4A, 4B and 4C are cross-sectional views taken along line A-A′ inFIG. 3 for showing manufacturing steps of the LCD device according tothe first embodiment of the present invention.

[0052] In a reflection type LCD device or a semi-transmissive type LCDdevice, in order to form a prominence and depression portions on areflection electrode, the reflection electrode is coated on an organicinsulation layer having a rugged surface to have a rugged shape afterthe organic insulation layer is exposed and developed to have theprominence and the depression portions on the surface of the organicinsulation layer. A full exposure process for double organic insulationlayers, a partial exposure process for a single organic insulation layeror a silt exposure process for a single organic insulation layer can bepresented as the process for forming the rugged surface on the organicinsulation layer.

[0053] In the present embodiment, a method for minimizing the step inthe pad region by using the double organic insulation layers through thefull exposure process will be described.

[0054] Referring to FIGS. 3 and 4A, a thin film transistor as aswitching device is formed on a first substrate 100 composed of anon-conductive material such as glass or ceramic. At first, a metal suchas molybdenum (Mo), chrome (Cr), tantalum (Ta), titanium (Ti), copper(Cu) or tungsten (W) is deposited on the first substrate 100 to from ametal layer. The first substrate 100 is divided into a first region 170and a second region 180. The first region 170 includes a pixel region171 where a pixel is formed to produce an image and a portion of aperipheral region 172 around the pixel region 171. A pad is not formedin the first region 170 of the first substrate 100. The second region180 is a pad region where a pad connected to the pixel is formed so asto apply an electric signal to the pixel. That is, the pixel region 171is positioned at a central portion of the first substrate 100 and theperipheral region 172 is positioned at peripheral portion of the firstsubstrate 100. In FIG. 4A, the second region 180 is formed in theperipheral region 172. Namely, the second region 180 is formed a portionof the peripheral region 172.

[0055] The metal layer is patterned by the photolithography method sothat a gate line 115 and a gate electrode 105 branched from the gateline 115 are formed in the pixel region 171 of the first region 170where the pixel is formed to produce the image. At the same time, inorder to apply the electrical signal to the pixel, a gate input pad 110elongated from the gate line is formed in the second region 180corresponding to a portion of the peripheral region 172 around the pixelregion 171 of the first region 170 of the first substrate 100. In thiscase, the gate input pad 110 has an area wider than that of the gateelectrode 105 and also the area of the gate pad 110 is wider than thatof the gate line 115. The gate electrode 105, the gate input pad 110 andthe gate line 115 may be formed by using an alloy includingaluminum-copper (Al—Cu) or aluminum-silicon-copper (Al—Si—Cu).

[0056] Referring to FIG. 4B, a silicon nitride (Si_(x)N_(y)) layer isdeposited to form a gate insulation layer 120 on the first substrate 100on which the gate electrode 105, the gate input pad 110 and the gateline 115 are formed. The silicon nitride layer is formed by the plasmachemical vapor deposition method.

[0057] Then, after an amorphous silicon layer and an in-situ doped n⁺amorphous silicon layer are formed on the gate insulation layer 120 bythe plasma chemical vapor deposition method, the amorphous silicon andthe n⁺ amorphous silicon layers are patterned to form a semiconductorlayer 130 and an ohmic contact layer 135 on the gate insulation layer120 under which the gate electrode 105 is positioned. In this case, thesemiconductor layer 130 may be transformed into a polysilicon layer byirradiating a laser having a predetermined intensity onto the amorphoussilicon layer.

[0058] Subsequently, after a metal layer composed of aluminum,molybdenum, tantalum, titanium, chrome, tungsten or copper is formedover the first substrate 100 having the resultant structure thereon, themetal layer is patterned to form a data line 160 perpendicular to thegate line 120, to form a source electrode 140 branched from the dataline 160 and to form a data input pad 150 connected to the data line160. Thus, a TFT 155 including the gate electrode 105, the semiconductorlayer 130, the ohmic contact layer 135, the source electrode 140 and thedrain electrode 145 is formed in the first region 170 positioned at thecentral portion of the first substrate 100. Also, the gate input pad 110and the data input pad 150 are formed in the second region 180positioned at the peripheral portion of the first substrate 100. Thesecond region 180 corresponds to a pad region. At that time, the gateinsulation layer 120 is interposed between the data line 160 and thegate line 120 to prevent an electrical short therebetween.

[0059] Referring to FIG. 4C, a photosensitive organic resist having athickness of about 2 to 3 μm is coated over the entire surfaces of thefirst and the second regions 170 and 180 of the first substrate 100 by aspin coating method, so a first organic insulation layer 190 is formed.

[0060] Referring to FIG. 4D, a first mask 185 is positioned over thefirst organic insulation layer 190 to expose a contact hole 175, thegate input pad 110, the data input pad 150 and their peripheralportions. A full exposing process is performed on the first organicinsulation layer 190 and then the contact hole 175 exposing the drainelectrode 145 of the TFT 155 is formed in the first organic insulationlayer 190 through a developing process. In this case, portions of thefirst organic insulation layer 190 formed on and around the gate anddata input pads 110, 150 in the second region 180 are removed during thefull exposing and the developing processes. That is, a portion of thefirst organic insulation layer 190 formed on and around the peripheralportion of the first substrate 100 under which the gate input pad 110 ispositioned besides the pixel region 171 is removed during the fullexposing and the developing processes. Also, a portion of the firstorganic insulation layer 190 formed on and around the data input pad 150(namely, the portion of the first organic insulation layer 190positioned in the second region 180) is removed. At that time, the gateinsulation layer 120 formed in the second region 180 is removed by a dryetching process and by using the first organic insulation layer 190 as amask to expose the gate input pad 110.

[0061] Referring to FIG. 4E, in order to form an insulation layer forinsulating the gate and the data input pads 110, 150 to prevent anelectrical short between the gate input pad 110 and the data input pad150, a second organic insulation layer 195 is formed on the first region170 and the second regions 180 of the first substrate 100. That is, thesecond organic insulation layer 195 is formed on the active region 170and the pad region 180 after an organic resist identical to the firstorganic insulation layer 190 is coated on the active and the pad regions170, 180 respectively corresponding to the first and the second regions170, 180. The organic resist is coated by the spin coating method andthe second organic insulation layer 195 has a thickness of about 0.5 toabout 1.5 μm, preferably about 1.0 μm. Therefore, the second organicinsulation layer covers the second region 180 including the gate inputpad 110, the data input pad 150 and the peripheral portions of the pads110, 150.

[0062] Then, a second mask 200 is positioned over the second organicinsulation layer 195 to form a rugged structure 205 on the secondorganic insulation layer 195 and to form an opening 176 exposing thedata input pad 150. Continuously, the pixel region 171 is exposed with alens exposure amount so as to form the rugged structure 205 composed ofa plurality of micro lenses on the second organic insulation layer 195positioned on the pixel region 171 of the first region 170 of the firstsubstrate 100. Also, a portion of the second organic insulation layer195 in the second region 180 is exposed to form the opening 176. Afterthe developing process is executed, the rugged structure 205 is formedon the second insulation layer 195 and the gate input pad 110 is exposedthrough the opening 176. At that time, the data input pad 150 is alsoexposed.

[0063] The rugged structure 205 consists of relatively high portions andrelatively low portions. That is, the rugged structure 205 has aplurality of protrusions having relatively high heights and a pluralityof grooves having relatively low heights. In this case, the depth of thegroove (or the height of the protrusion) is about 0.5 to about 1.0 μm.

[0064] As it is described above, the step between the portion where thegate and the data input pads 110, 150 are positioned and the portionadjacent the pads 110, 150 can be greatly reduced since the secondorganic insulation layer 195 formed on the second region 180 isconsiderably thin and the gate and the data input pads 110, 150 areexposed through the exposing and the developing processes after thefirst organic insulation layer 190 formed on the second region 180corresponding to the pad region is removed.

[0065] With reference to FIG. 4F, after a metal having excellentreflectivity such as aluminum, nickel, chrome or silver (Ag) is coatedon the pad region 180, on the surfaces of the first organic insulationlayer 190 and the second organic insulation layer 195 having the ruggedstructure 205 and in the contact hole 175 exposing the drain electrode145, the metal is patterned to form a reflection electrode 210 having ashape of the pixel in the pixel region 171 of the first substrate 100.Hence, the reflection electrode 210 has a rugged surface according tothe rugged structure 205 of the first and the second organic insulationlayers 190, 195. In this case, a pad electrode 215 is formed on the gateinput pad 1 10 and the data input pad 150. The pad electrode 215 has adull shape and has a height smaller than the depth of the contact hole175. The successive manufacturing processes for the LCD device of thepresent invention are the same as those of the conventional method formanufacturing the LCD device.

[0066]FIG. 4G is a cross-sectional view showing the completed LCD deviceaccording to the present embodiment. Referring to FIG. 4G, after a firstorientation layer 300 is formed on the resultant structure, a secondsubstrate 305 opposed to the first substrate 100 is disposed on thefirst substrate 100. The second substrate 305 includes a color filter310, a common electrode 315, a second orientation layer 320, a phaseplate 325 and a polarization plate 330. The second substrate 305 is madeof a material identical to the first substrate 100 such as glass orceramic. The phase plate 325 and the polarization plate 330 are formedon the second substrate 305 in such an order. The color filter 310 ispositioned beneath the second substrate 305 and the common electrode 315and the second orientation layer 320 are formed beneath the color filter310 in that order.

[0067] A liquid crystal layer 230 is inserted in a space provided byinterposing a plurality of spacers between the first substrate 100 andthe second substrate 305, thereby accomplishing a reflection type LCDdevice or a semi-transmissive type LCD device.

[0068] Then, after an anisotropic conductive film 290 having conductiveballs 292 is coated on the input pads 110, 150 formed in the pad region180 of the first substrate 100, a bump 294 of a COG, a COF or an FPC iscompressed and then the input pads 110, 150 are connected the COG, theCOF or the FPC, thereby completing a reflection type LCD module or asemi-transmissive type LCD module.

[0069] As shown in FIG. 4G, the LCD device includes an insulation layercomposed of the first and the second organic insulation layers 190, 195.The first organic insulation layer 190 is formed in the first region 170where the pixel is formed and the first organic insulation layer 190 hasa thickness of about 2.5 to about 4.5 μm. Also, the LCD device has asecond organic insulation layer 195. The second organic insulation layer195 is formed in the pad region 180 and has a thickness of about 0.5 toabout 1.5 μm. The rugged structure 205 is formed on the surface of thefirst insulation layer 190 positioned on the pixel region 171 of thefirst region 170 where the pads 110, 150 are not formed. The secondorganic insulation layer 195 has the opening 176 exposing the pads 110,150.

[0070] According to the present embodiment, the step between the padsand the portion of the organic insulation layer adjacent the pads islower than the step between the contact hole and the portion of theorganic insulation layer adjacent the contact hole through exposing anddeveloping the double organic insulation layers composed of the firstand the second insulation layers. This may significantly reduce theconnection failure between the pads and the COG, the COF or the FPC whenthe COG, the COF or the FPC is compressed for connecting the COG, theCOF or the FPC to the pads of the LCD device.

Embodiment 2

[0071] In the first embodiment of the present invention, the secondorganic insulation layer is formed in the second region after the firstorganic insulation layer is removed through the full exposing process.However, the second organic insulation layer may be formed after aninsulation layer pattern for forming the rugged structure on the firstregion corresponding to the active region. Thus, the insulation layerpattern for forming the rugged structure is previously formed on theorganic insulation layer in the first region according a secondembodiment of the present invention.

[0072]FIGS. 5A, 5B, 5C and 5D are schematic cross-sectional viewsillustrating a method for manufacturing an LCD device according thesecond embodiment of the present invention.

[0073] Referring to FIG. 5A, a first organic insulation layer 190 isformed on a first region 170 of a first substrate 100 where a TFT 155 isformed according the processes shown in FIGS. 4A, 4B and 4C. Then, afirst insulation layer pattern 190 a for forming a rugged structure anda contact hole 175 are formed on and in the first organic insulationlayer 190 in the first region 170. After a first mask 185 is positionedover the first organic insulation layer 190 in the first region 170 soas to expose pad region 180 including a gate input pad 110, a data inputpad 150 and a peripheral portion adjacent to the pads 110, 150, a fullexposing process is proceeded with a predetermined exposure amount (thatis, the sufficient exposure amount to form the contact hole 175).Subsequently, a developing process is performed to form the contact hole175 exposing a drain electrode 145 of the TFT 155 in the first organicinsulation layer 190. In this case, the first insulation pattern 190 ais formed in a pixel region 171 for forming the rugged structure on asurface of a reflection electrode and a portion of the first organicinsulation layer 190 positioned on the gate and the data input pads 110,150 and on the peripheral portion adjacent to the pads 110, 150 in asecond region 180 is removed. Namely, the portion of the first organicinsulation layer 190 formed around the gate input pad 110 in aperipheral region 172 except the pixel region 171 is removed. Also, theportion of the first organic insulation layer 190 formed around the datainput pad 150 is simultaneously removed. Thus, the first organicinsulation layer 190 remains in the peripheral region 172 besides theportion of the second region 180 where the pads 110, 150 are positioned.

[0074] Referring to FIG. 5B, a second organic insulation layer 195 iscoated on the first region 170 and the second region 180 of the firstsubstrate 100. The second organic insulation layer 195 is formed by aspin coating method and has a thickness of about 0.3 to about 3 μm,preferably about 0.5 to 1.5 μm, more preferably about 1 μm. The secondorganic insulation layer 195 is composed of an organic resist identicalto the first organic insulation layer 190. The second organic insulationlayer 195 is positioned on the first insulation layer pattern 190 a andon the first substrate 100 including the first organic insulation layer190 formed thereon. Hence, the rugged structure 205 is formed in thepixel region 171 according to the first insulation layer pattern 190 aand the second organic insulation layer 195 is coated on the secondregion 180.

[0075] Subsequently, in order to form an opening 176 exposing the datainput pad 150 in the second region 180 and a contact hole 175 in thepixel region 171, a second mask 200 is positioned over the firstsubstrate 100. Then, the contact hole 175 is formed in the first organicinsulation layer 190 with a predetermined exposure amount for formingthe opening 176 and the opening 176 is formed in the second region 180to expose the gate and the data input pads 110, 150 after an exposingand a developing processes are performed.

[0076] The step between the pads 110, 150 and the portion of the secondorganic insulation layer 195 adjacent to the pads 110, 150 can begreatly decreased since the gate and the data input pads 110, 150 areexposed through the exposing and the developing processes after theportion of the first organic insulation layer 190 positioned in thesecond region 180 is removed and the second organic insulation layer 195having a low height is formed in the second region 180.

[0077] Referring to FIG. 5C, the reflection electrode 210 is formed bythe method identical to the method illustrated in FIG. 4F. Thus, therugged structure 205 is formed on the surface of the reflectiveelectrode 210 in the pixel region 179 according to shapes of the firstand the second organic insulation layers 190, 195. At that time, a padelectrode 215 is formed on the data and the gate input pads 110, 150 andthe pad electrode 215 is lower than that of the contact hole 175.

[0078]FIG. 5D is a cross-sectional view for showing a completed LCDdevice according to the present embodiment.

[0079] In the same manner as illustrated in FIG. 4G, after a firstorientation layer 300 is formed on the resultant structure on the firstsubstrate 100, a second substrate 305 is disposed on the first substrate100. The second substrate 305 includes a color filter 310, a commonelectrode 315, a second orientation layer 320, a phase plate 325 and apolarization plate 330.

[0080] After a plurality of spacers 335, 336 are interposed between thefirst substrate 100 and the second substrate 305, a liquid crystal layer230 in inserted in a space formed between the first and the secondsubstrates 100, 305 by the spacers 335, 336, so a reflection type or asemi-transmissive type LCD device is completed.

[0081] After an anisotropic conductive film 290 is positioned on theinput pads 110, 150 formed in the pad region 180 of the first substrate100, a bump 294 of a COG, a COF or an FPC is compressed so as to beconnected to the pads 110, 150, thereby accomplishing a reflection typeLCD module or a semi-transparence type LCD module.

[0082] As shown in FIG. 5D, in the completed LCD device according to thepresent embodiment, a first insulation layer having a thickness of about2.5 to about 4.5 μm is formed in the pixel region 171 and a secondinsulation layer having a thickness of about 0.5 to about 1.5 μm isformed in the second region 180.

[0083] The first insulation layer includes the first insulation layerpattern 190 a and the second organic insulation layer 195. That is, thefirst insulation layer formed in the first region 170 includes the firstinsulation layer pattern 190 a in the pixel region 171 for forming thereflection electrode pattern and also the second insulation layerincludes the first organic insulation layer 190 formed in the peripheralregion 172 and the second organic insulation layer 195 having theopening 176 exposing the pads 110, 150 in the second region 180. Thesecond organic insulation layer 195 has the rugged structure thereon inaccordance with the first insulation layer pattern 190 a and extends tothe second region 180.

[0084] According to the present embodiment, the full exposing process isperformed about the active region for forming the contact hole and theinsulation layer pattern and the exposing process is simultaneouslyconcerning the pad region for forming the opening after the firstorganic insulation layer is previously formed. Thus, the contact holeand the insulation layer pattern are formed in the active region forforming the reflection electrode and the portion of the first organicinsulation layer is selectively removed in the pad region after thedeveloping process. Subsequently, after the second organic insulationlayer is coated on the resultant structure, the developing process isexecuted concerning the active region for forming the contact hole inthe second organic insulation layer and the pad region for forming theopening and then, the developing process is performed. Therefore, thestep of the organic insulation layer between the pads and the portionadjacent to the pads can be decreased to be lower than the step aroundthe contact hole, thereby greatly reducing the connection failureillustrated in FIG. 2 when the COG, the COF or the FPC is connected tothe pads of the LCD device.

Embodiment 3

[0085]FIGS. 6A, 6B, 6C and 6D are cross-sectional views for illustratinga process for forming an organic insulation layer according to a thirdembodiment of the present invention. While the double organic insulationlayers are formed in accordance with the first and the secondembodiments, a single organic insulation layer is formed to reduce astep in a pad region according to the present embodiment.

[0086] A TFT 155 is formed on a first substrate 100 according to theprocesses described in FIGS. 4A, 4B and 4C. Referring to FIG. 6A, anorganic resist is coated on a first region 170 and a second region 180of the first substrate 100 having the TFT 155 thereon by the spincoating method to form an organic insulation layer 165 having athickness of about 2.4 to about 4.0 μm.

[0087] Subsequently, after a first mask 185 is positioned over theorganic insulation layer 165 for forming a contact hole 175 and anopening 176 respectively exposing a drain electrode 145 of the TFT 155and a pad 110, a primary exposing process is executed concerning theorganic insulation layer 165 with a full exposing amount (that is, afull exposing process for forming the contact hole 175 in the organicinsulation layer 165). When the organic insulation layer 165 isdeveloped, the contact hole 175 and the pad opening 176 aresimultaneously formed as shown in a dotted line. The contact hole 175 isformed in a pixel region 171 of the first region 170 to expose the drainelectrode 145 and the pad opening 176 is formed in the second region 180to expose the gate and the data input pads 110, 150.

[0088] Referring to FIG. 6B, after a second mask 200 for forming areflection electrode is positioned over the organic insulation layer165, a secondary exposing process is executed concerning the organicinsulation layer 165 in the first region 170 and the whole surface ofthe second region 180 with a lens exposure amount (namely, the exposingamount for forming lenses of the reflection electrode). In this case,the secondary exposing process is accomplished by a partial exposingmethod with the lens exposure amount or a slit exposing method.

[0089] Then, a rugged structure 205 is formed on the organic insulationlayer 165 in the pixel region 171 and the opening 176 is formed in theorganic insulation layer 165 positioned in the second region when theexposed organic insulation layer 165 is developed. The opening 176 isformed through removing the organic insulation layer 165 around the pads110, 150 in the second region 180. Hence, the step between the gateinput pad 110 and the portion adjacent to the gate input pad 110 can bereduced because the organic insulation layer 165 is partially removedwhile preventing shorts between the input pads 110, 150 in the secondregion 180. Also, the step between the data input pad 150 and theportion adjacent to the data input pad 150 can be minimized while theorganic insulation layer 165 partially remains between each of the datainput pad 150. At that time, the thickness of the organic insulationlayer 165 in the second region is about 0.3 to about 3.0 μm.

[0090] The rugged structure 205 on the pixel region 171 includes aplurality of grooves and protrusions and has a height (the depth of thegroove or the height of the protrusion) of about 0.5 to about 1.0 μm.The thickness of the organic insulation layer 165 is about 1.0 to about3.0 μm on the basis of the groove of the rugged structure 205. Hence,the thickness of the organic insulation layer 165 in the pixel region171 is reduced by about 0.2 to about 1.0 μm on the basis of theprotrusion of the rugged structure 205. In this case, the gate and thedata input pads 110, 150 are exposed according as the gate insulationlayer 120 in the opening 176 of the pad region 180 by a dry etchingmethod.

[0091] Referring to FIG. 6C, the reflection electrode 210 is formed bythe process described in FIG. 4F. Thus, the reflection electrode 210 inthe pixel region 171 has a rugged structure thereon in accordance withthe rugged structure 205 of the organic insulation layer 165. At thattime, the pad electrode 215 is formed on the gate and the data inputpads 110, 150. The pad electrode 215 is higher than the contact hole175.

[0092]FIG. 6D is a cross-sectional view showing a completed LCD deviceaccording to the present embodiment. In the same manner as described inFIG. 4G, after a first orientation layer 300 is formed on the resultantstructure on the first substrate 100, a second substrate 305 opposed tothe first substrate 100 is disposed on the first substrate 100. Thesecond substrate 305 includes a color filter 310, a common electrode315, a second orientation layer 320, a phase plate 325 and apolarization plate 330.

[0093] After a plurality of spacers 335, 336 are interposed between thefirst substrate 100 and the second substrate 305, a liquid crystal layer230 in inserted in a space formed between the first and the secondsubstrates 100, 305 by the spacers 335, 336, thereby completing areflection type or a semi-transmissive type LCD device.

[0094] After an anisotropic conductive film 290 including conductiveballs 292 is formed on the input pads 110, 150 formed in the pad region180 of the first substrate 100, a bump 294 of a COG, a COF or an FPC iscompressed so as to be connected to the pads 110, 150, therebyaccomplishing a reflection type LCD module or a semi-transmissive typeLCD module.

[0095] As shown in FIG. 6D, in the completed LCD device according to thepresent embodiment, an insulation layer having a thickness of about 0.5to about 4.0 μm is formed in the first region 170. In this case, theinsulation layer has a thickness of about 0.5 to about 4.0 μm in thepixel region 171 and has a thickness of about 2.5 to about 4.0 μm in theperipheral region around the pixel region 171. Also, the insulationlayer having a thickness of about 0.3 to about 3.0 μm is formed in thepad region 172. The rugged structure 205 is formed on the portion of theinsulation layer in the pixel region 171 and the opening 176 is formedin the portion of the insulation layer in the pad region 172. At thattime, the thickness of the insulation layer in the pixel region 171 maybe less than that of the insulation layer in the second region 180 byadjusting the exposing amount during the secondary.

Test of Effect for Improving the Step Between the Pads in AccordanceWith the Partial Exposing Process

[0096] An LCD device is manufactured according to the method of thethird embodiment of the present invention. The organic insulation layerof the LCD device is about 3.0 to about 4.0 μm thick. The steps betweenthe pads are measured without the partial exposing process or the slitexposing process. The measured steps are shown in table 1. TABLE 1 DataThe First COG The Second COG FPC Pad Input Pad COG Input Pad Output Padstep (μm) 3.4 3.4 4.0 3.2

[0097] According to the method described in FIG. 5B, the partialexposing process is executed concerning the input and the output pads ofthe COG by changing the exposure amount. The measured steps between thepads are shown in table 2 after the partial exposing process isperformed. In this case, the partial exposing process or the slitexposing process is not performed concerning the pad of the FPC. TABLE 2The Second Partial Exposing Data FPC Pad The First COG COG Input Pad COGOutput Pad Amount (ms) (μm) Input Pad (μm) (μm) (μm) 2500 3.40 1.36 1.601.18 2600 3.56 1.30 1.58 1.10 2700 3.40 1.15 1.39 0.96 2800 3.45 1.101.35 0.91 2900 3.48 1.03 1.26 0.82 3000 3.46 0.96 1.19 0.75 3100 3.500.90 1.05 0.66 3200 3.48 0.80 1.00 0.60

[0098] As shown in table 1 and table 2, the steps between the input andthe output pads of the COG are greatly reduced and also linearlydecreased as the partial exposure amount is increased. The lens exposureamount corresponds to about 2600 ms for forming the rugged structure onlayer as the lenses. Under such lens exposure amount, the step isreduced by about 1.1 to about 1.6 μm when the insulation layer in thepad region is partially exposed. Therefore, step between the first andthe second region is decreased by about 2.1 to about 2.4 μm incomparison with the conventional manufacturing method in which thepartial exposing performed.

[0099] According to the present invention, it can be minimized that theheight difference between one portion of the organic insulation layer inthe pad region and the other portion of the organic insulation layeradjacent to the pad region by exposing and developing single organicinsulation layer or double organic insulation layers. Therefore, it cansignificantly decrease the connection failure between the pads of theLCD device and the COG, the COF, the FPC when the COG, the COF, the FPCis compressed to the pads of the LCD device.

[0100] Also, the electrical short between the pads of the LCD device canbe prevented since the organic insulation layer remains between the padswhile the step between the pads is greatly decreased.

[0101] Furthermore, the step in the pad region can be minimized withoutperforming another process for reducing the step since that the heightdifference between the height difference between one portion of theorganic insulation layer in the pad region and the other portion of theorganic insulation layer adjacent to the pad region is reduced when theorganic insulation layer is exposed and developed so as to from thecontact hole and the reflection electrode.

[0102] In the above-described embodiments of the present invention, thereflection type or the semi-transmissive type LCD device ismanufactured, however, any display device having a thick insulationlayer and a pad electrode may be manufactured according to the method ofthe present invention. For example, a transmission type LCD device maybe manufactured by the method of the above-described methods of thepresent invention.

[0103] Although the preferred embodiments of the present invention havebeen described in detail with reference to drawings and specific termshave been used, the present invention is not limited to theabove-described embodiments and various modifications may be evidentlyeffected by one skilled in the art within the scope and spirit of thepresent invention.

What is claimed is:
 1. A display device, comprising: a substratecomprising: a first region including: a pixel region including a pixelfor producing an image; and a peripheral region surrounding the pixelregion; and a second region including a pad connected to the pixel forapplying an electrical signal from outside to the pixel; and aninsulation layer formed on the first and second regions with an openingformed in the insulation layer to expose the pad, wherein the insulationlayer has a first thickness in the opening and a second thickness in theperipheral region, and second thickness is greater than the firstthickness.
 2. The display device as claimed in claim 1, wherein thepixel region is arranged on the substrate, the peripheral region isarranged around the pixel region and the peripheral region surrounds thesecond region.
 3. The display device as claimed in claim 2, wherein thepixel comprises a thin film transistor as a switching device, and thepad comprises a gate input pad and a data input pad.
 4. The displaydevice as claimed in claim 1, wherein the second thickness is about 0.3to about 3.0 μm.
 5. The display device as claimed in claim 1, wherein adifference between the second thickness and the first thickness is about2.1 to about 2.4 μm.
 6. The display device as claimed in claim 1,wherein a rugged structure is formed on the insulation layer in thepixel region.
 7. The display device as claimed in claim 6, wherein athickness of the insulation layer in the pixel region is no more thanthe second thickness.
 8. The display device as claimed in claim 1,wherein the insulation layer comprises a first organic insulation layerformed in the first region and a second organic insulation layer formedin the first and the second regions wherein the second organicinsulation layer comprises a rugged structure formed in the pixel regionand an opening formed in the second region.
 9. The display device asclaimed in claim 1, wherein the insulation layer comprises: firstinsulation layer patterns having reflective electrode patterns of afirst insulation layer formed in the pixel region and peripheralpatterns of the first insulation layer covering the peripheral region;and a second insulation layer having a rugged structure in the pixelregion and an opening exposing the pad in second region wherein thesecond insulation layer covers the first insulation layer patterns andthe second insulation layer is continuously formed form the first regionto the second region.
 10. A reflection type liquid crystal displaydevice, comprising: a first substrate having a first region and a secondregion wherein the first region includes a pixel region on the firstsubstrate where a pixel is formed to produce an image and a peripheralregion surrounding the pixel region and a pad connected to the pixel isformed on the second region for applying an electrical signal to thepixel from outside; a second substrate opposed to the first substrate; aliquid crystal layer formed between the first substrate and the secondsubstrate; a reflection electrode formed at the central portion of thefirst substrate, the reflection electrode having a rugged structurecomprising a relatively high portion and a relatively low portion; andan organic insulation layer formed between the first substrate and thereflection electrode and formed in the first region and the secondregions wherein the organic insulation layer has a rugged structureidentical to the rugged structure of the reflection electrode at acentral portion of the first region and an opening in the second regionto expose the pad, and a second thickness of the organic insulationlayer around the opening is less than a first thickness of the organicinsulation layer in the peripheral region.
 11. The reflection typeliquid crystal display device as claimed in claim 10, wherein the ruggedstructure comprises a plurality of protrusions and a plurality ofgrooves.
 12. The reflection type liquid crystal display device asclaimed in claim 10, wherein the second thickness is about 0.3 to about3.0 μm.
 13. The reflection type liquid crystal display device as claimedin claim 10, wherein a difference between the second thickness and thefirst thickness is about 2.1 to about 2.4 μm.
 14. The reflection typeliquid crystal display device as claimed in claim 10, wherein athickness of the organic insulation layer in the pixel region is nogreater than the second thickness.
 15. A method for manufacturing adisplay device, comprising the steps of: forming a pixel in a pixelregion of a first region of a substrate, the first region including thepixel region and a peripheral region around the pixel region, andforming a pad in a second region of the substrate for applying anelectric signal to the pixel; forming an insulation layer having anopening in the second region to expose the pad and wherein theinsulation layer being formed in the first region and the second regionand a second thickness of the insulation layer around the opening isless than a first thickness of the insulation layer in the first region;and forming a pad electrode in the opening and on the insulation layerformed around the opening in the second region.
 16. The method formanufacturing a display device as claimed in claim 15, wherein the pixelregion is positioned on the substrate and the second region ispositioned in the peripheral region of the substrate.
 17. The method formanufacturing a display device as claimed in claim 16, wherein the pixelcomprises a thin film transistor as a switching device and the padcomprises a gate input pad and a data input pad for applying an electricsignal to the switching device.
 18. The method for manufacturing adisplay device as claimed in claim 15, further comprising forming areflection electrode on the insulation layer in the pixel region andforming a pad electrode on the pad in the second region.
 19. The methodfor manufacturing a display device as claimed in claim 18, wherein thereflection electrode and the pad electrode are simultaneously formed bycoating a metal layer composed of a reflective metal on the insulationlayer and by patterning the metal layer.
 20. The method formanufacturing a display device as claimed in claim 15, wherein the stepfor forming the insulation layer further comprises the steps of: forminga first insulation layer on the substrate; selectively removing thefirst insulation layer in the second region; forming a second insulationlayer in the first region and in the second region; and forming theopening in the second insulation layer.
 21. The method for manufacturinga display device as claimed in claim 20, wherein the first insulationlayer and the second insulation layer are composed of organic resists.22. The method for manufacturing a display device as claimed in claim20, wherein the step for removing the first insulation layer in thesecond region further comprises: forming a contact hole in the firstinsulation layer for connecting the pixel; full exposing the firstinsulation layer with an exposure amount for forming the contact holeafter a first mask is positioned over the first insulation layer toremove the first insulation layer; and developing the exposed firstinsulation layer.
 23. The method for manufacturing a display device asclaimed in claim 20, wherein the step for forming the opening in thesecond insulation layer further comprises the steps of: forming a ruggedstructure on the second insulation layer after a second mask ispositioned over the second insulation layer; exposing the secondinsulation layer with an exposure amount identical to an exposure amountfor forming the rugged structure after the second mask for forming theopening is positioned over the second insulation layer; and developingthe exposed second insulation layer.
 24. The method for manufacturing adisplay device as claimed in claim 15, wherein the step for forming theinsulation layer further comprises: forming a first insulation layer onthe substrate; patterning the first insulation layer to form aninsulation layer pattern in the pixel region and to selectively removethe first insulation layer in the second region; forming a secondinsulation layer in the first region and the second region; and formingan opening in the second insulation layer in the second region.
 25. Themethod for manufacturing a display device as claimed in claim 24,wherein the step for patterning the first insulation layer furthercomprises: positioning a first mask on the first insulation layer forforming a rugged structure and a contact hole; full exposing the firstinsulation layer with an exposure amount for forming the contact hole;and developing the exposed first insulation layer.
 26. The method formanufacturing a display device as claimed in claim 25, wherein the stepfor forming the opening is performed by positioning a second mask overthe second insulation layer for forming the contact hole and theopening, exposing the second insulation layer and developing the exposedsecond insulation layer.
 27. The method for manufacturing a displaydevice as claimed in claim 15, wherein the step for forming theinsulation layer further comprises the steps of: forming an organicinsulation layer on the substrate; primarily exposing the organicinsulation layer with a full exposure amount for removing the organicinsulation layer on the pad; partially exposing the organic insulationlayer in the second region; and forming an opening in the second regionand partially removing the organic insulation layer around the openingin the second region by developing the exposed organic insulation layer.28. The method for manufacturing a display device as claimed in claim27, wherein the step for primarily exposing the organic insulation layeris performed by exposing the organic insulation layer with a fullexposure amount after a first mask is positioned over the organicinsulation layer for forming the opening and a contact hole forelectrically connecting the pixel.
 29. The method for manufacturing adisplay device as claimed in claim 28, wherein the step for partiallyexposing the organic insulation layer is performed by exposing theorganic insulation layer and the second region with a lens exposureamount for forming a reflection electrode on the organic insulationlayer.